Why do alkaleaks leak and have they always been this bad? - eviltoast

I remember using them as a kid and leaking wasn’t unknown, but it seemed less frequent than now. Have they gotten worse, and why? Cost reduction? Thinner casings due to capacity races like happened with NiMH in the early 2000s? Changed formulations from earlier less safe materials? Just my imagination and they always leaked like now? Or what? Thanks.